LONDON (Reuters) - An $8 billion hedge fund run by billionaire Michael Platt has yet to give investors all their money back nine months after the fund was shuttered, a spokesman for the fund and three of its investors told Reuters.

BlueCrest, which ran more than $30 billion at its peak, making more than $22 billion for investors since it launched 15 years ago, was best known for bets on macroeconomic trends.

But Platt shut BlueCrest late last year. He told investors in a letter on Dec. 1, seen by Reuters, that a decision to close the firm was prompted by increased costs and investor pressures. He told investors in the Dec. 1 letter they would get 90 percent of their money by late March.

That initial timetable has slipped and the company has told investors it needs more time to pay back what is owed, which for the three investors amounts to millions of dollars.

Lengthy payouts can be common when hedge funds close, a scenario not often anticipated by most investors. But as the list of hedge fund closures outpaced launches globally for the third consecutive quarter, according to data from Hedge Fund Research, it is more crucial than ever that investors understand all terms and conditions before signing on the dotted line.

While some BlueCrest investors have been happy to see their money returned gradually to protect returns and avoid a firesale of assets, one of the three investors that spoke to Reuters said the process had taken too long.

This investor, who declined to be named, said he was frustrated by the slow payout from AllBlue Limited, a BlueCrest fund of funds.

"We are frustrated that (the fund) provided quarterly liquidity when we decided to invest and it's still not clear how long it will take to get all of our money back," he said.

"If a hedge fund offers quarterly liquidity, it should take a maximum of six months to liquidate and that's being generous."

AllBlue Limited had advertised that investors could access their capital every quarter with a 33-day notice period - known as quarterly liquidity, documents seen by Reuters showed.

At the end of the first quarter, AllBlue Limited, which invested in a number of the BlueCrest's individual funds, had paid out about 79 percent of investors' cash, approximately 11 percent shy of initial hurdles, a spokesman at BlueCrest told Reuters.

Investors would have received more than 91 percent of their investment in AllBlue Limited by the end of the third quarter, he said, but he declined to say when the remainder would be paid out.

"Inevitably, the exact timing of each portfolio liquidation will be determined by the assets comprised in it and prevailing market conditions," the spokesman for BlueCrest said.

Investors were also offered the opportunity to invest in AllBlue Limited, which gave them access to all seven underlying funds.

Platt said in his letter on Dec. 1 that BlueCrest would aim to pay back about 75 percent of cash by the end of January 2016 in its AllBlue funds, growing to 90 percent by the end of March 2016, with the remainder "as soon as practicable."

London's Camden Pension fund, one of the three investors, said in a statement on Aug. 26 that the AllBlue fund-of-funds was still waiting to get money back from three underlying funds - Capital International, Multi Strategy Credit and Mercantile.

"It is expected that remaining funds will be sold and funds returned in due course," the pension fund, which had invested 58 million pounds ($76.73 million), said.

It was not known how much investor cash in total was allocated to the AllBlue Limited fund when it shut on Dec. 1. BlueCrest's spokesman said the suite of AllBlue funds had $8.1 billion.

The three investors told Reuters they were still awaiting payment, but the payouts were in line with a revised timetable, given after Dec. 1, but not made public.

Camden Council told Reuters via email they had received just over 79 percent of their money by the end of the first quarter. U.S.-based Stamford Police Pension Fund, which had $3 million invested with BlueCrest, confirmed in documents seen by Reuters it had also received funds according to BlueCrest's updated timetable.

BlueCrest's spokesman said investors had received quarterly update letters providing a detailed progress report on each fund's asset-liquidation program, including expected timings of future distributions and summaries of the remaining asset portfolios. He declined to comment on the payout schedule for the remaining AllBlue funds.

Thomas Deegan, managing director at investment consultant Clearbrook, who advises the Stamford Police Pension on its investment in BlueCrest, said BlueCrest had done "an honourable job" of keeping it abreast of repayments and managing an orderly liquidation of assets.